.box{
	
	width: 200px;
	height: 200px;
	border: 1px solid green;
	float: left;
	font-size:  40px;
	text-align: center;
	
}
.bigbox{
width: 200px;
	height:500px;
	width: 500px;
	border: 1px solid red;
	
	
}
.clearfix::after{
	  content: "";  /* 内容为空 */ 
	 display: block;  /* 格式转换 */
	height: 0px;
	clear: both; /*清除俩端浮动*/
	visibility: hidden; /*隐藏*/

	
}
.clearfix::before,.clearfix::after{
	content: "";
	display: table;
	
}
